<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <script src="https://cdn.jsdelivr.net/npm/vue@2.6.10/dist/vue.js"></script>
    <title>Document</title>
    <style>
        .one {
            width: 100px;
            height: 100px;
            background-color: yellow;
        }
        .two {
            width: 200px;
            height: 200px;
            background-color: rgb(140, 255, 0);
        }
        .three {
            width: 300px;
            height: 300px;
            background-color: rgb(255, 204, 0);
        }
        .active {
            color:rgb(200, 159, 238)
        }
    </style>
</head>
<body>
    <div id="app">
        <!-- class强制绑定写法允许是一个对象写法,对象的key就是类名,如果这个key对应的value是truthy的值,则这个类开启 -->
        <div v-bind:class="className"></div><br/>
        <div :class="className"></div>
        <p :class = "isActive ? 'active' : ''">这是一个段落</p>
        <p :class = "{active: isActive}">这是一个段落2</p>
    </div>
    <script>
        const vm = new Vue({
            data() {
                return {
                   className: {
                        one: true,
                        two: false,
                        three: false
                   },
                   isActive: true
                }
            }
        }).$mount('#app');

    </script>
</body>
</html>